JP7102237B2 - Target material cleaning method, equipment for that purpose, target material manufacturing method and target material, recycled ingot manufacturing method and recycled ingot - Google Patents

Description

The present invention relates to a method for cleaning a target material in a recycling process of a used sputtering target, an apparatus for that purpose, a method for producing a target material and a target material using the same, a method for producing a recycled ingot, and a recycled ingot.

In a sputtering target, a target material generally composed of ceramics such as metal, alloy, or oxide and a support member such as a backing plate or backing tube composed of metal or alloy are bonded by a bonding material such as a solder material. By subjecting such a sputtering target to sputtering, a thin film such as a metal or an oxide can be formed on the substrate. Regardless of the type of target material, it is not completely consumed by sputtering, but is recovered after its use, and metals such as aluminum and copper are melted again and cast to form ingots (slabs, ingots). ) Can be reused (recycled).

Regarding the recycling of the sputtering target, for example, Patent Documents 1 to 3 disclose the removal of surface deposits on the sputtering target by mechanical removal such as acid treatment and blast treatment.

Japanese Unexamined Patent Publication No. 2005-23350 Japanese Unexamined Patent Publication No. 2005-23349 International Publication No. 2015/151498 Pamphlet

Treatments such as acid treatment and blast treatment are laborious and time-consuming, and are extremely complicated. Further, the thickness of the bonding material remaining on the used target material is mainly not uniform, which is particularly remarkable in the target material for a large-sized flat panel display. Therefore, it is difficult to completely remove the joining material by acid treatment or blasting treatment with dilute nitric acid, and there is a risk that the joining material remains in a part. Further, in the blasting treatment, since the media made of metal or ceramics collides with the processing portion, there is a concern that the media remains, and particularly when the target material is a high-purity product, contamination by the media becomes a problem. Therefore, components derived from media and joining materials can be mixed as impurities in the ingot obtained by melting and casting the used target material, so that the quality of the recovered material is equivalent to that of the original target material. It was difficult to regenerate the target material. In addition, components derived from support members such as backing plates and backing tubes may also be mixed as impurities.

Therefore, in the present invention, a method for cleaning a target material capable of easily removing a bonding material from a used target material without using an acid or a medium, an apparatus for that purpose, a method for manufacturing a target material using them, and a method for manufacturing the target material using them. An object of the present invention is to provide a method for producing a recycled ingot in which the amount of impurities derived from a target material, a joining material and a support member is reduced, and a recycled ingot.

As a result of diligent research, the present inventor separates the target material from the support member after use in a sputtering target in which a target material mainly composed of metal and a support member are bonded by a bonding material, and then the target. It has been found that the adhered bonding material can be easily removed from the target material by cleaning the target material by spraying water on the surface on which the bonding material of the material adheres and remains. Further, they have found that the amount of impurities derived from the joining material and the supporting member can be significantly reduced by obtaining a recycled ingot using the target material treated by such a method as a raw material, and have completed the present invention.

The present invention is characterized in that a recycled ingot is obtained from the following target material cleaning method, an apparatus for that purpose, a target material manufacturing method and target material using them, and a target material treated by the cleaning method or apparatus as a raw material. The present invention may be provided, but the present invention is not limited to the following.

[1]
The target material is separated from the support member of the sputtering target (or the sputtering target after use) in which the target material mainly composed of metal and the support member are bonded by the bonding material, and at least the bonding of the target material is performed. A method for cleaning a target material, which comprises removing the bonding material from the target material by injecting water onto a surface to which the material is attached (or a surface to which the material is attached and remains).
[2]
The method for cleaning a target material according to the above [1], wherein the pressure of the water is 90 MPa or more.
[3]
The method for cleaning a target material according to the above [1] or [2], wherein the metal is aluminum or copper.
[4]
A method for producing a target material (or a used target material), which comprises treating the target material by the cleaning method according to any one of the above [1] to [3].
[5]
The energy dispersive X-ray fluorescence analysis is characterized in that elements contained in impurities derived from the bonding material and the supporting member of the sputtering target in which the target material and the supporting member are bonded by the bonding material are not substantially detected. Target material (or used target material) after cleaning.
[6]
A recycled ingot containing the metal is obtained by casting the metal using the target material (or used target material) obtained by the production method described in the above [4] as a raw material. Production method.
[7]
A recycled ingot characterized in that the total amount of impurities derived from the bonding material and the supporting member of the sputtering target formed by bonding the target material and the supporting member with the bonding material is less than 10 ppm on a weight basis.
[8]
The recycled ingot according to the above [7], wherein the metal that is the main component of the recycled ingot is aluminum or copper.
[9]
The recycled ingot according to the above [8], wherein the metal that is the main component of the recycled ingot is aluminum, and the total amount of the impurities is less than 5 ppm on a weight basis.
[10]
Water is sprayed onto at least the surface of the target material to which the joint material is attached, which is separated from the support member of the sputtering target in which the target material mainly composed of metal and the support member are bonded by the joint material. This is a device used to remove the bonding material from the target material.
At least one nozzle head provided with at least one injection port for injecting water onto the target material, and
An actuator for operating the nozzle head and
An apparatus in which the actuator is arranged and includes a processing chamber for accommodating and processing the target material.
[11]
The device according to [10] above, further comprising a clamp for fixing the target material in the processing chamber.
[12]
The device according to the above [10] or [11], further comprising a reversing mechanism for reversing the target material.
[13]
Any one of the above [10] to [12], which includes a drainage mechanism for collecting and draining the water sprayed from the injection port and separating the processed material containing the bonding material removed from the target material. The device described in the section.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a cleaning method and a cleaning device for a target material capable of easily removing a bonding material by injecting water. Further, by obtaining a recycled ingot from the target material treated by such a method or an apparatus as a raw material, the amount of impurities derived from the joining material and the supporting member can be significantly reduced. For example, if the target material is mainly composed of aluminum or copper, the total amount of impurities can be less than 10 ppm by weight.

It is the schematic which shows the outline of this invention. It is the schematic which shows the coupling between the target material of a sputtering target and a support member. It is the schematic which shows the coupling between the target material of another sputtering target and the support member. It is the schematic which shows the coupling of the target material of another sputtering target, and the support member. It is a schematic perspective view which shows typically the embodiment of the apparatus which can be used in this invention. It is a schematic top view which shows typically the embodiment of the apparatus which can be used in this invention. It is the schematic which shows the cross section of the apparatus shown in FIG. 6 in AA. It is the schematic which shows the cross section of the apparatus shown in FIG. 6 in BB. It is the schematic which shows typically the relationship between the actuator 103 and the nozzle head 102 shown in FIGS. 5 to 8. It is the schematic which shows typically the membrane separation type solid-liquid separation apparatus as an example of a drainage mechanism. It is the schematic which shows typically the multi-stage settling tank as an example of a drainage mechanism.

The present invention relates to a method for cleaning a target material, an apparatus for that purpose, a method for producing a target material using them, a target material, a method for producing a recycled ingot using the target material treated by the cleaning method or the apparatus as a raw material, and the production thereof. Regarding recycled ingots produced by the method.

For example, as shown in the schematic view of FIG. 1, a sputtering target generally melts a metal and processes an ingot obtained by casting (for example, after subjecting the obtained ingot to plastic working such as rolling or extrusion). A target material having a shape such as a flat plate type or a cylindrical shape is produced by machining (machining such as cutting and polishing), and the target material and a separately produced support member such as a backing plate or a backing tube are joined to each other. It can be made by binding or joining using. According to the present invention, the sputtering target is separated into a target material and a support member after being used in sputtering as described in detail below, and the used target material is a joining material by cleaning by injecting water. Can be made into an ingot by removing and remelting and casting (hereinafter referred to as "recycled ingot"), and the target material can be produced again by processing this recycled ingot.

Method for cleaning target material In the present invention, the "sputtering target" is a target material mainly composed of a metal (element) and a support member bonded by a bonding material, and can be used for sputtering. If there is, there is no particular limitation. When the sputtering target is a flat plate type, a flat plate backing plate can be used as the support member. When the sputtering target is cylindrical, a cylindrical backing tube can be used as the support member. Here, a cylindrical backing tube can be inserted inside the cylindrical target material, and the inner peripheral portion of the cylindrical target material and the outer peripheral portion of the backing tube can be joined by a joining material.

The "target material" can be mainly composed of a metal (element), for example, aluminum (Al), copper (Cu), chromium (Cr), iron (Fe), tantalum (Ta), and titanium (Ti). ), Zirconium (Zr), Tungsten (W), Molybdenum (Mo), Niob (Nb), Silver (Ag), Cobalt (Co), Ruthenium (Ru), Platinum (Pt), Palladium (Pd), Gold (Au) ), Rodium (Rh), iridium (Ir), and nickel (Ni), which contain a metal (element) selected from the group, and may be an alloy containing the above metals, and have a Vickers hardness of 200 or less. It is preferably a metal or alloy, preferably 100 or less, more preferably 50 or less. Of these, it is preferably composed mainly of aluminum (purity 99.99% (4N) or higher, preferably purity 99.999% (5N) or higher) or copper (purity 99.99% (4N) or higher). The Vickers hardness can be confirmed by the Vickers hardness test (JIS Z 2244: 2003). There are no particular restrictions on the dimensions, shape and structure of the target material. It is preferable to use a plate-shaped target material.

When the target material has a plate shape, the dimensions of the target material in the longitudinal direction are, for example, 500 mm to 4000 mm, preferably 1000 mm to 3200 mm, and more preferably 1200 mm to 2700 mm.
The dimensions in the width direction (direction perpendicular to the longitudinal direction) are, for example, 50 mm to 1200 mm, preferably 150 mm to 750 mm, and more preferably 170 mm to 300 mm.
The thickness is, for example, 5 mm to 35 mm, preferably 10 mm to 30 mm, and more preferably 12 mm to 25 mm.
In the present invention, for example, even a target material for a large flat panel display can be easily processed.

When the support member is a "backing plate", it is mainly copper (Cu), chromium (Cr), aluminum (Al), titanium (Ti), tungsten (W), molybdenum (Mo), tantalum (Ta), niobium. It contains a metal (element) selected from the group consisting of (Nb), iron (Fe), cobalt (Co) and nickel (Ni), and may be an alloy containing the above metals, and among them, Copper (oxygen-free copper), chromium copper alloy, aluminum alloy and the like are preferable. There are no particular restrictions on the dimensions, shape and structure of the backing plate as long as it is a plate-like material on which the target material can be placed.
When the support member is a "backing tube", the metal constituting the support member is the same as that of the backing plate described above, but among them, stainless steel (SUS), titanium, a titanium alloy, or the like is preferable. The dimensions of the backing tube are usually longer than the cylindrical target material because they are inserted and joined inside the cylindrical target material, and the outer diameter of the backing tube is preferably slightly smaller than the inner diameter of the cylindrical target material. ..

The "joining material" is not particularly limited as long as it can be used to form a sputtering target by contributing to the bonding between the target material and the support member (FIG. 2). The joining material includes, for example, a solder material, a brazing material, and the like.
The "solder material" is a material containing a metal or alloy having a low melting point (for example, 723K or less), and is, for example, indium (In), tin (Sn), zinc (Zn), lead (Pb), silver (Ag). , Copper (Cu), Bismus (Bi), Cadmium (Cd) and Antimony (Sb), and materials containing metals selected from the group or alloys thereof. More specifically, In, In-Sn, Sn-Zn, Sn-Zn-In, In-Ag, Sn-Pb-Ag, Sn-Bi, Sn-Ag-Cu, Pb-Sn, Pb-Ag, Examples thereof include Zn-Cd, Pb-Sn-Sb, Pb-Sn-Cd, Pb-Sn-In, and Bi-Sn-Sb.
As the "wax material", a metal or alloy having a melting point lower than that of the target material and the support member can be used without particular limitation as long as the target material and the support member can be bonded to each other.
As the bonding material, it is preferable to use a solder material such as In or In alloy, Sn or Sn alloy, which generally has a low melting point.

For example, the solder material can be bonded by forming a diffusion layer (alloy layer) with the metal (element) contained in the target material on the bonding surface with the target material by heating. Further, the solder material can also form and bond a diffusion layer (alloy layer) with the metal (element) contained in the support member on the joint surface with the support member. Therefore, by using such a solder material, a solder layer can be formed and the target material and the support member can be bonded (FIG. 3).

In general, simply placing the above-mentioned solder material on the target material or the support member may not provide sufficient bonding strength due to the influence of the oxide film that may exist on the surface of the target material or the support member. Therefore, first, a metallized layer may be provided in order to improve the wettability of the solder material with respect to their surfaces.

"Metallizing" is a treatment method that can be generally used to form a metal film on a non-metal surface. In the present invention, for example, when the target material or the support member has an oxide film, the solder for metallizing is used. It means that a metallized layer is formed by combining a material with a target material or a support member. The metallized layer uses, for example, an ultrasonic soldering iron to destroy the oxide film of the target material and the support member by the vibration energy (cavitation effect) of the ultrasonic wave, and by heating, together with the oxygen atoms in the oxide film. It can be formed by chemically bonding a metal atom contained in a solder material for metallization and a metal atom contained in a target material or a support member.

The metallized layer (5, 5') (see FIG. 4) that can be formed in this way can also be bonded to the above-mentioned solder layer (4), and is between the target material (1) and the solder layer (4). , Located between the support member (2) and the solder layer (4), the role of firmly connecting the target material (1) and the solder layer (4), and the support member (2) and the solder layer (4). Can be fulfilled.

The thickness of the solder layer is, for example, in the range of 50 μm to 500 μm in the case of the flat plate type and 250 μm to 1500 μm in the case of the cylindrical type.
The thickness of the metallized layer is, for example, in the range of 10 μm to 100 μm for both the flat plate type and the cylindrical type.

The solder materials that can be used for metallization are, for example, indium (In), tin (Sn), zinc (Zn), lead (Pb), silver (Ag), copper (Cu), bismuth (Bi), and cadmium (Cadmium). A material containing a metal selected from the group consisting of Cd) and antimony (Sb) or an alloy thereof, and more specifically, In, In—Sn, Sn—Zn, Sn—Zn—In, In—Ag. , Sn-Pb-Ag, Sn-Bi, Sn-Ag-Cu, Pb-Sn, Pb-Ag, Zn-Cd, Pb-Sn-Sb, Pb-Sn-Cd, Pb-Sn-In, Bi-Sn -Sb and the like can be mentioned. A material having a high affinity with the target material or the support member may be appropriately selected.

In the present invention, for example, as shown in the schematic view of FIG. 1, after the sputtering target is used in sputtering, the target material is separated (peeled) from the support member. There is no particular limitation on the method of separating the target material from the support member. For example, heat (for example, 180 ° C. to 300 ° C.) is applied to a joint layer (or joint layer) that can be formed from the above-mentioned joint material to soften or melt the joint layer while physically forming the joint layer as necessary. It can be broken to separate the target material from the support member.

When the target material is a flat plate type, in the target material after separation, the surface on the side that has been bonded (or joined) to the backing plate (hereinafter, may be referred to as "bonding surface" or "joining surface") , At least a part of the bonding material is attached and remains. Even if the joining material adhering to the joint surface after separation is scraped off with a spatula (for example, a spatula made of silicone), the adhering joining material cannot be completely removed. Further, the joining material may adhere and remain on the sputtering surface of the target material. The causes are, for example, that the bonded material melted during the separation of the target material adheres to the sputtering surface, and that the separated used target materials are stacked and stored, so that the bonding surface and the sputtering surface come into contact with each other. However, the bonding material on the bonding surface may adhere to the sputtering surface. Therefore, the cleaning method may be applied to the sputtering surface as well.

When the target material is cylindrical, the cylindrical target material can be bonded to the outer peripheral portion of the cylindrical backing tube by using a bonding material. Therefore, as in the case of the plate-shaped target described above, the target material after separation is bonded. The bonding material adheres to the surface (inner circumference) and cannot be completely removed. Further, the joining material may adhere and remain on the sputtering surface of the target material. Furthermore, components derived from the backing tube may also be mixed as impurities. Therefore, even in the cylindrical target material, the cleaning method may be applied to the outer peripheral portion and the inner peripheral portion which are the sputtering surfaces.

The presence or absence of adhesion of the bonding material in the target material after separation can be confirmed by, for example, Energy Dispersive X-ray Fluorescence Analysis (EDXRF). In addition, metal elements may diffuse from the support member to the target material, and such metal elements can also be confirmed by EDXRF. In addition, Wavelength Dispersive X-ray Fluorescence Analysis (WDXRF), Electron Probe Micro Analysis (EPMA), Auger Electron Spectroscopy (AES), X X-ray Photoelectron Spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectroscopy (TOF-SIMS), Laser Irradiation Induced Combined Plasma Mass Spectroscopy (LA-) Although impurities derived from the bonding material and supporting member can be confirmed by analysis methods such as ICP-MS: Laser Ablation Inductively Coupled Plasma Mass Spectrometry) and X-ray Diffraction Analysis (XRD), Confirmation by EDXRF or WDXRF is preferable because of its simplicity and wide analysis range.

Here, the ingot (hereinafter, may be referred to as “slab” or “ingot”) is manufactured by melting and casting in the subsequent recycling process using the separated target material to which the joining material is attached as it is. Then, when the target material is manufactured again from this ingot, impurities derived from the components of the adhered joint material are mixed. Further, the metal element may diffuse from the support member to the target material and be mixed as an impurity, and such a metal element may also be mixed as an impurity in the ingot.

Therefore, in the present invention, after the used target material is separated from the support member, at least the target material is cleaned by spraying water onto the surface on which the joint material of the target material adheres and remains, and the adhered joint material is adhered. Can be removed from the target material (Fig. 1).

The method of injecting water is not particularly limited, but it is preferable to inject water under the following conditions.

The water injection can be performed using, for example, a pump, and it is preferable to inject water at a high pressure (hereinafter, it may be referred to as a “water jet”). The pressure for injecting water is, for example, 90 MPa or more, preferably 90 MPa to 350 MPa, more preferably 150 MPa to 280 MPa, and further preferably 150 MPa to 250 MPa. If the injection pressure is low, the cleaning effect may not be sufficient to remove the bonding material, especially the chemically strongly bonded metallized layer. Conversely, if the injection pressure is too high, the target material itself is deepened beyond the metallized layer. It may be scraped, resulting in poor yield or high equipment costs.

Water is preferably sprayed using a rotary (or rotatable) nozzle head having a plurality of jet ports (or nozzles). The shape of the nozzle head is not particularly limited, and the shape of the surface of the nozzle head facing the target material (or the surface on which the nozzle is installed) is, for example, a polygon such as a triangle or a square, or a circle. Although it has an elliptical shape, it is rotated to inject water, so a regular polygon such as a circle or a square is preferable, and a perfect circle is more preferable. Further, when treating the joint surface of the flat plate type target material, it is possible to use a nozzle head capable of attaching an injection port so that water is ejected in a direction substantially parallel to the rotation axis of the nozzle head. preferable. When processing the joint surface (inner circumference) of the cylindrical target material, use a nozzle head that can be equipped with an injection port so that water is ejected in a direction substantially perpendicular to the rotation axis of the nozzle head. It is preferable to do so.

The number of injection ports (or the number of nozzles) provided in one nozzle head is not particularly limited, and is, for example, one or more, preferably 1 to 15, and more preferably 3 to 10. The number of nozzles may be appropriately determined according to the size of the nozzle head, and if the number of nozzles is small, uncut parts may be left uncut or the processing time may be long. Further, if the number of nozzles is large, the total discharge amount increases, so that a larger and more expensive pump is required, which may increase the equipment cost. When a plurality of injection ports are provided on the nozzle head, the injection ports may be arranged at the same diameter position of the nozzle head or at different diameter positions. Further, it may be a combination of the same diameter arrangement and the different diameter arrangement.

The dimensions (nozzle diameter) of the injection port are, for example, 0.1 mm or more, preferably 0.15 mm to 0.50 mm, and more preferably 0.2 mm to 0.35 mm. Injection ports having the same diameter may be attached to the nozzle head, or injection ports having different diameters may be combined and attached to the nozzle head.

The amount of water discharged (or the amount of water) changes according to the pressure of the water to be sprayed and the size of the injection port, and the larger the amount, the higher the cleaning effect. The total discharge amount of water ejected from all the injection ports of one nozzle head is, for example, 2.0 L / min or more, preferably 2.0 L / min to 42 L / min, and more preferably 5.0 L / min to. It is 30 L / min, more preferably 5.0 L / min to 20 L / min.

It is preferable that the water is sprayed by moving in a horizontal direction in a strip shape (line shape) at a constant speed while maintaining a constant distance from the treated surface of the target material. Further, the water may be sprayed several times, preferably once to three times, at the same place. Alternatively, when the treatment width in one water injection is smaller than the target width, the water may be sprayed by partially overlapping (overlapping) in a line shape.

The moving speed of the nozzle head is, for example, 100 mm / min or more, preferably 500 mm / min to 7000 mm / min, and more preferably 900 mm / min to 5000 mm / min. If the moving speed is low, the processing time becomes long, and if the moving speed is high, the cleaning effect may not be sufficient.

The rotation speed of the nozzle head is, for example, 500 min ^-1 or more, preferably 500 min ^-1 to 4000 min ^-1 , and more preferably 900 min ^-1 to 2500 min ^-1 . If the rotation speed is too low, water may not hit the entire surface of the target material and uncut parts may be left depending on the number of nozzles. If the rotation speed is too high, the impact when hitting the target material will be small, which is sufficient. A good cleaning effect may not be obtained.

The distance (or nozzle distance) between the nozzle head and the target material is, for example, 10 mm or more, preferably 15 mm to 100 mm, and more preferably 20 mm to 70 mm. If the distance is too close, it may be affected by the water that bounces off the target material and a sufficient cleaning effect may not be obtained. If the distance is too large, the impact when hitting the target material will be small, which is sufficient. The cleaning effect may not be obtained.

The water to be sprayed is not particularly limited as long as it does not contain particulate impurities or dust that clog the nozzle, and examples thereof include the use of tap water and pure water. Further, a filter may be provided between the pump and the nozzle, and water may be injected through the filter.

The direction of water injection is not particularly limited as long as the angle at which the water hits the target material, and may be perpendicular to or oblique to the target material. For example, the angle of the injection port (the angle formed by the central axis of the injection port and the perpendicular to the target material) is 0 ° to 60 °, preferably 0 ° to 45 °, more preferably 5 ° to 45 °, still more preferable. Is 5 ° to 30 °, more preferably 8 ° to 30 °, and particularly preferably 10 ° to 25 °. When water is sprayed diagonally to the target material, the processing width is larger than when water is sprayed vertically because the nozzle head is rotating. In addition, the water that hits the target material does not stay on the treated surface but escapes to the outside, so that the cleaning effect is expected to be improved. Further, when water is sprayed obliquely from the nozzle head, the side surface can be cleaned with the nozzle head positioned above the target material. Regarding the treatment of the joint surface of the target material, the treatment of the sputtering surface, and the treatment of the side surface, it is not necessary to reset the target material or change the position of the nozzle head, so that the processing time can be shortened. However, if the angle is too large, the distance between the target material and the nozzle will increase. In addition, since the impact when hitting the target material is small, a sufficient cleaning effect may not be obtained. When a plurality of injection ports are provided in the nozzle head, the angles of the nozzles may be the same or different. The angle of each injection port may be appropriately determined so that the desired treatment width and the uncut portion due to the absence of water are not left.

The nozzle head may scan a plurality of nozzle heads at the same time in order to shorten the processing time per target material.

In the above, the case where a rotary nozzle head is used has been described, but when the target material can be rotated or when a flat-firing nozzle head in which water is sprayed linearly is used, a fixed nozzle head is used. Can also be used to efficiently clean the target material.

When the joint material and the metallized layer are sufficiently removed from the joint surface of the used target material by cleaning, the cleaned surface can be satin-finished. Further, periodic processing marks (scale-like, spiral-like, etc.) may be formed according to the movement of the nozzle head during cleaning. In the case of a satin finish, for example, the specular reflectance of the washed surface at a wavelength of 300 nm to 1500 nm is 1.0% or less, and it is confirmed that impurities derived from the bonding material and the supporting member are sufficiently removed. Is preferably 0.7% or less. Further, the rate of change of the regular reflectance (regular reflectance of the cleaned surface / the regular reflectance of the surface before cleaning) with respect to the wavelength of each incident light at a wavelength of 300 nm to 1500 nm is preferably 0.025 or more and 0.85 or less. Is 0.05 or more and 0.75 or less, more preferably 0.08 or more and 0.60 or less, and further preferably 0.10 or more and 0.40 or less. It can be confirmed that the target material has been sufficiently removed, and it is possible to prevent the target material from being scraped too much.
The arithmetic mean roughness Ra is 5 μm or more, preferably 10 μm or more in order to confirm that impurities derived from the bonding material and the support member are sufficiently removed, and the arithmetic mean roughness before and after cleaning. The rate of change of Ra (arithmetic mean roughness Ra of the washed surface / arithmetic mean roughness Ra of the surface before washing) is 4 or more and 80 or less, preferably 5 or more and 50 or less, more preferably 7.5 or more and 20. Hereinafter, the cleaning treatment may be more preferably performed so as to be 10 or more and 15 or less. Usually, the arithmetic mean roughness Ra is 100 μm or less, preferably 50 μm or less. If the arithmetic mean roughness Ra is too large, foreign substances such as dust and sand are likely to adhere, the thickness of the oxide film becomes thick, and impurities in the recycled ingot may increase.

According to the cleaning method of the present invention, the lower limit of detection of EDXRF (usually, the lower limit of detection differs depending on the element, but for example, the lower limit of detection of impurities derived from the bonding material is about 0.01% by weight, for example, indium. The amount of impurities derived from the bonding material and the supporting member can be reduced to a value lower than (0.01% by weight), and is contained in the impurities derived from the bonding material and the supporting member in the target material after cleaning. The element is substantially not detected (or the target material after cleaning is substantially free of elements contained in impurities derived from the bonding material and the support member).

In the present invention, "elements contained in impurities derived from the joining material and the supporting member are substantially not detected" (or "elements contained in the impurities derived from the joining material and the supporting member are substantially not contained"). Means that, as described above, the amount of elements contained in the impurities derived from the bonding material and the support member is reduced to the extent that it is smaller than the lower limit of detection of EDXRF and cannot be detected by EDXRF.

Further, the cleaning method of the present invention is different from the method of processing a flat surface at a certain height position such as cutting with a milling cutter, and the surface of the target material (or work) hit by the sprayed water. Since it is a method of efficiently scraping only only the target material, it is possible to process with a high yield even if the target material has irregularities and distortions, and the target has not only the joint surface of the target material but also the irregularities formed by sputtering. It is also suitable for cleaning the sputtering surface of materials and the joint surface inside a cylindrical target. Further, the cleaning method of the present invention can be easily performed without taking time for setting and cleaning because the work can be set without worrying about the height of the processed surface. Therefore, it is different from the conventional methods such as blasting and cutting. Has many advantages compared to.

Device The present invention also relates to a device that can be used in the cleaning methods described above. Specifically, at least the joint material of the target material (or used target material) separated from the support member of the sputtering target in which the above-mentioned target material mainly composed of metal and the support member are bonded by the joint material is used. The present invention relates to a device used for removing a bonding material from a target material by injecting water onto an adhering surface (hereinafter, may be simply referred to as a “cleaning device”).

The cleaning device may include at least the following configurations (a) to (c).
(A) At least one nozzle head provided with at least one injection port for injecting water onto the target material (b) Actuator for operating or moving the nozzle head (c) An actuator is arranged to accommodate the target material. Processing room for processing

For example, as shown in FIGS. 5-8, the apparatus 100 is at least
A nozzle head 102 having at least one injection port (not shown) capable of injecting water onto the used target material (or work) 101.
An actuator capable of operating (or moving) the nozzle head 102, preferably an X-axis slider 103X, a Y-axis slider 103Y, and a Z-axis slider 103Z, is provided, and the nozzle head 102 can be moved in any direction of the XYZ axes. An actuator 103 configured to be movable and
It includes a processing chamber 104 in which the actuator can be arranged and the target material 101 can be accommodated and processed (or washed).
In the illustrated embodiment, the target material 101 is described as a flat plate type, but the target material 101 that can be used in the device 100 is not limited to the flat plate type.

-Nozzle head The nozzle head can be used without particular limitation as long as it is provided with at least one injection port (or nozzle) capable of injecting water. Further, the number of nozzle heads used is not particularly limited. When a plurality of nozzle heads are used, it is preferable to arrange them at appropriate intervals so that the water ejected from the nozzles does not interfere with each other.
Further, the apparatus of the present invention may be separately provided with a nozzle head (or a side nozzle head) for spraying water onto the side surface of the work for cleaning. There is no particular limitation on the number of nozzle heads used to process the side surfaces of the work (XZ plane and / or YZ plane) and the position where they are arranged.
As the nozzle head, those described in detail in the above-mentioned "Method for cleaning the target material" can be appropriately used without limitation.
Further, a rotary unit for rotating the nozzle head may be further provided.

-Actuator As the actuator, for example, an actuator that can operate or move the nozzle head by using a driving force such as electricity, hydraulic pressure, or pneumatic pressure may be used. It is preferable to use a nozzle that can arbitrarily and appropriately move the nozzle head in at least one direction of the X-axis, the Y-axis and the Z-axis, and more preferably in all the directions of the X-axis, the Y-axis and the Z-axis.
More specifically, in order to move the nozzle head in all directions of the X-axis, the Y-axis, and the Z-axis, for example, as shown in FIGS. 5 to 9 (particularly, FIG. 9), the X-axis slider 103X and Y A three-axis combination type actuator 103 including an axis slider 103Y and a Z-axis slider 103Z can be used.

The nozzle head 102 is configured to be directly or indirectly coupled to the Z-axis slider 103Z via, for example, a rod 106, if necessary, and is configured by the Z-axis slider 103Z in the Z-axis direction ( The nozzle head 102 can be moved in the vertical direction or in the direction toward or away from the surface to be processed of the target material 101 (FIG. 9). In yet another aspect, the Z-axis slider 103Z may be configured such that the rod 106 penetrates and passes through the inside thereof.

The Z-axis slider 103Z is configured to be physically or mechanically coupled to the Y-axis slider 103Y, and the Y-axis slider 103Y causes the nozzle head 102 together with the slider 103Z in the Y-axis direction (of the target material 101). It can be moved along the traveling direction or the direction perpendicular to the longitudinal direction of the device 100 or the target material 101 shown (FIG. 9).

The Y-axis slider 103Y is configured to be physically or mechanically coupled to the X-axis slider 103X, and the X-axis slider 103X causes the nozzle head 102 to be connected to the X-axis slider 103Y and 103Z in the X-axis direction (target material). It can be moved along the traveling direction of 101 or the longitudinal direction of the device 100 or the target material 101 (FIG. 9). Further, even if the end of the Y-axis slider 103Y opposite to the end connected to the X-axis slider 103X is engaged with a support guide (or guide rail) that can be arranged in parallel with the X-axis slider 103X. good.

By using the actuator 103 (FIG. 9) including the sliders 103X, 103Y and 103Z, the nozzle head 102 can be appropriately moved in the three directions of the X-axis, the Y-axis and the Z-axis.

The sliders 103X, 103Y and 103Z are not particularly limited in their driving mode and coupling mode as long as they can be slidably moved to each other by using driving force such as electricity, hydraulic pressure, and pneumatic pressure.

The movement of the nozzle head and the injection of water by the actuator may be controlled by an electronic program. In that case, each slider may be appropriately connected by an electric cable or the like. It is desirable to control the moving speed of the nozzle head and the injection of water as defined in the above-mentioned "Method for cleaning the target material".

The actuator may be waterproof, and the waterproof specification can prevent problems caused by rust or running out of oil caused by the spray of water sprayed or splashing on the target material coming into contact with the actuator. Further, when connecting each slider of the actuator with an electric cable, it is preferable that the electric cable is also waterproof.

As in the illustrated embodiment, water may be sprayed vertically downward from the nozzle head, but a mechanism capable of changing the angle of the nozzle head may be further arranged as needed. In that case, the angle of the nozzle head can also be controlled by an electronic program. Further, by such a mechanism, the cylindrical target material can be cleaned more efficiently.

As the actuator, for example, a 3-axis combination type industrial robot manufactured by IAI Co., Ltd. may be used.

The actuators that can be used in the apparatus of the present invention should not be construed as being limited to the above.

-Processing chamber The processing chamber can arrange the above-mentioned actuator together with the nozzle head, and the main purpose is to accommodate the target material and process the target material according to the above-mentioned "method for cleaning the target material". ..

In addition, by treating the target material in the treatment chamber, the water sprayed from the nozzle head hits the target material and the spray is generated, and the solid processed material (or dust) including the joining material removed from the target material is scattered around. It can prevent the environment from being polluted.

For example, as shown in FIGS. 5 to 8, the processing chamber 104 has a rectangular body, the upper portion thereof is open, and an actuator (specifically, an actuator including sliders 103X, 103Y, 103Z shown in FIG. 9) is included. It is configured so that 103) can be arranged.

The dimensions of the processing chamber 104 are not particularly limited, and it is preferable that the target material for a large sputtering target can be processed.

When the target material 101 is conveyed along its longitudinal direction as in the illustrated embodiment, the ratio (X / Y) of the dimension in the X-axis direction and the dimension in the Y-axis direction of the processing chamber 104 is, for example, 3/16. It is ~ 10/1, preferably 1/2 to 10/3, and more preferably 6/7 to 7/3.
The ratio (X / Z) of the dimension in the X-axis direction to the dimension in the Z-axis direction is, for example, 1/3 to 10/1, preferably 1/2 to 4/1, and more preferably 5/6 to 35/12. Is.
The ratio (Y / Z) of the dimension in the Y-axis direction to the dimension in the Z-axis direction is, for example, 1/5 to 8/1, preferably 3/5 to 2/1, and more preferably 5/6 to 35/24. Is.

In the above case, the dimensions in the X-axis direction are, for example, 750 mm to 5000 mm, preferably 1000 mm to 4000 mm, and more preferably 1500 mm to 3500 mm.
Specifically, the dimensions in the Y-axis direction are, for example, 500 mm to 4000 mm, preferably 1200 mm to 2000 mm, and more preferably 1500 mm to 1750 mm.
Specifically, the dimensions in the Z-axis direction are, for example, 500 mm to 2500 mm, preferably 1000 mm to 2000 mm, and more preferably 1200 mm to 1750 mm.

In the illustrated embodiment, the target material 101 is conveyed along the longitudinal direction by using the conveying means 105 such as a belt conveyor and a roller described in detail below, and the target material is conveyed inside the processing chamber 104. Although it can be processed, the target material 101 is conveyed along the width direction (direction perpendicular to the longitudinal direction) of the target material 101 (for example, along the Y axis), and the target material 101 is conveyed inside the processing chamber 104. 101 may be processed.

When the target material 101 is conveyed along its width direction (direction perpendicular to the longitudinal direction), the ratio (X / Y) of the dimension in the X-axis direction and the dimension in the Y-axis direction of the processing chamber 104 is, for example, 3 /. It is 16 to 10/1, preferably 1/2 to 10/3, and more preferably 6/7 to 7/3.
The ratio (X / Z) of the dimension in the X-axis direction to the dimension in the Z-axis direction is, for example, 1/3 to 10/1, preferably 1/2 to 4/1, and more preferably 5/6 to 35/12. Is.
The ratio (Y / Z) of the dimension in the Y-axis direction to the dimension in the Z-axis direction is, for example, 1/5 to 8/1, preferably 3/5 to 2/1, and more preferably 5/6 to 35/24. Is.

In the above case, the dimensions in the X-axis direction are, for example, 750 mm to 5000 mm, preferably 1000 mm to 4000 mm, and more preferably 1500 mm to 3500 mm.
Specifically, the dimensions in the Y-axis direction are, for example, 500 mm to 4000 mm, preferably 1200 mm to 2000 mm, and more preferably 1500 mm to 1750 mm.
Specifically, the dimensions in the Z-axis direction are, for example, 500 mm to 2500 mm, preferably 1000 mm to 2000 mm, and more preferably 1200 mm to 1800 mm.

When the transport means 105 is used, the processing chamber 104 may have a pair of openings (carry-in port, carry-out port) through which the transport means 105 and the target material 101 pass. The size of the opening is not particularly limited as long as the target material 101 can be passed through.

When the target material 101 is conveyed along the longitudinal direction as in the illustrated embodiment, the dimension of the opening in the Y-axis direction is, for example, 100 mm or more, preferably 150 mm to 1500 mm, more preferably 200 mm to 1000 mm. Even more preferably, it is 250 mm to 500 mm, and the dimension in the Z-axis direction is, for example, 10 mm or more, preferably 12 mm to 300 mm, more preferably 20 mm to 200 mm, and even more preferably 45 mm to 150 mm.

When the target material 101 is conveyed along its width direction (direction perpendicular to the longitudinal direction), the dimension of the opening in the X-axis direction is, for example, 500 mm or more, preferably 750 mm to 4000 mm, and more preferably 1000 mm to 3500 mm. It is even more preferably 1500 mm to 3000 mm, and the dimension in the Z-axis direction is, for example, 10 mm or more, preferably 12 mm to 300 mm, more preferably 20 mm to 200 mm, and even more preferably 45 mm to 150 mm.

In the above embodiment, the device capable of transporting the target material 101 has been described, but the cleaning device of the present invention does not have to be provided with the transporting means 105.

In the embodiment shown in FIG. 5, it is shown that the processing chamber 104 also has an opening on its side surface (XX surface) so that the inside of the processing chamber 104 can be clearly seen. , May or may not exist. When such an opening exists, an openable door (for example, a double door) may be provided in the opening to prevent spraying or scattering of dust. Providing such a door is preferable because maintenance inside the processing chamber 104 is simplified.

Water (including a solid processed product (or dust) containing a bonding material removed from the target material) after being sprayed from the nozzle head to wash the target material 101 is provided at the bottom of the inside of the processing chamber 104 (hereinafter, A pool (not shown) for temporarily storing (referred to as "treated water") may be provided.

Further, the inside of the treatment chamber 104 may have a discharge port (not shown) for discharging the treated water. The discharge port may be arranged on the bottom surface of the treatment chamber 104, but since the processed material may accumulate and block the discharge port, an interval of, for example, 1 mm to 50 mm, preferably 10 mm to 25 mm from the bottom surface may be provided. It can also be opened and placed on the side. The shape, dimensions, and structure of the discharge port are not particularly limited as long as the treated water can be discharged.

Further, the inside of the processing chamber 104 may optionally be provided with a shower mechanism for washing away the processed material adhering to the inner wall surface of the processing chamber 104.

The processing chamber that can be used in the apparatus of the present invention should not be construed as being limited to the above.

Other Configurations The device may include other configurations in addition to the above configurations.

Clamps The apparatus of the present invention may further include clamps for fixing the target material in the processing chamber. By fixing the target material with a clamp, the target material can be fixed so as not to move during the cleaning process. There is no particular limitation on the position where the clamp is placed in the processing chamber. It is preferable to fix the side surfaces of the target material from both sides thereof. By fixing in this way, water can be sprayed over the entire surface of the target material to be treated without being covered with the clamp.
Further, when the target material is deformed, for example, when it is bent in a bow shape, when water is sprayed from the upper side of the target material, the target material may vibrate and the performance of the cleaning process may be deteriorated. By fixing the side surface of the target material with a clamp as described above, the vibration of the target material can be suppressed.
If the target material has little warpage or if there is a base under the target material, water is sprayed from vertically above the target material, so that the target material does not move from a predetermined position determined in advance. All you have to do is fix it.
In addition, by fixing the target material to a predetermined position determined in advance with a clamp (positioning of the target material), there is an advantage that it is not necessary to perform 0 point adjustment (designation of the processing range) when operating the nozzle head. Be done.
The shape and dimensions of the clamp are not particularly limited, but it is preferable to use a clamp capable of fixing the side surfaces of the target material from both sides as described above. For example, a side clamp manufactured by Imao Corporation or Tsudakoma Corp. can be used. The number of clamps and the position where the clamps are arranged are not particularly limited, and may be appropriately determined according to the target material.
The clamp mechanism may be automatic or manual, but in order to simplify the work of fixing a large target material, when the target material is installed at a predetermined position, the target material is used. It is preferable that the side surface is an automatic type that is sandwiched from both sides. When the clamp is a manual type, it is preferable to provide an opening, preferably an openable door, on the side surface (XX surface) of the processing chamber 104 from the viewpoint of workability.

-Transport mechanism The apparatus of the present invention may include a transport mechanism capable of carrying the target material into the processing chamber and carrying out the target material from the processing chamber (for example, the transport means 105 shown in FIGS. 5 to 8). ..
The transport mechanism can be used without particular limitation as long as it can transport the target material. For example, a conveyor such as a belt conveyor, a roller conveyor, a caterpillar, a shuttle conveyor, a pallet conveyor, a vacuum chuck conveyor, etc. Robot arm transfer and the like can be mentioned.
The transport speed of the target material by the transport mechanism is not particularly limited, but is, for example, 15 m / min to 60 m / min, preferably 20 m / min to 50 m / min, and more preferably 25 m / min to 40 m / min.
Further, the transport mechanism may form a continuous loop so that the target material can be carried into the processing chamber again after being carried out from the processing chamber.
The transport mechanism may be arbitrarily divided according to the purpose of loading, unloading, processing chamber, loop, and the like.
Further, the transport mechanism may be provided with a target material supply mechanism on the inlet side of the processing chamber, or may be provided with a target material reversing mechanism on the outlet side of the processing chamber.

-Target material supply mechanism The apparatus of the present invention may include a target material supply mechanism so that the target material can be appropriately supplied to the above-mentioned transport mechanism. The target material supply mechanism is not particularly limited as long as the target material can be appropriately supplied. Further, the target material supply mechanism may include a cassette for storing a plurality of target materials, and may be capable of appropriately supplying the target material from the cassette. .. A commercially available automatic supply device may be used as the target material supply mechanism.

-Target material reversing mechanism The apparatus of the present invention further includes a reversing mechanism for reversing the target material, preferably a mechanism capable of reversing the target material in a fixed state (for example, fixed with a clamp or the like). good. By including such an inversion mechanism, the surface to be processed of the target material can be arbitrarily inverted. The dimensions of the reversing mechanism are not particularly limited.
A commercially available automatic reversing device may be used, and for example, an automatic reversing device manufactured by Adpec Co., Ltd. can be used.

-Drainage mechanism Since the treated water after cleaning the target material contains a solid treated product (or dust) containing the bonding material removed from the target material, the apparatus of the present invention can be used as necessary. It may include a drainage mechanism capable of recovering and draining only water from the treated water, and separating a solid treated matter such as a bonding material.
The drainage mechanism can be used without particular limitation as long as it can separate the solid and the liquid. In the art, a generally well-known solid-liquid separator or the like can be appropriately used as needed.
The drainage mechanism is preferably connected to a drainage port that may be provided inside the treatment chamber.

For example, a membrane separation type solid-liquid separation device that can be generally used for water treatment can be used. In a membrane separation type solid-liquid separator, water is suction-filtered by a pump through a water collecting pipe connected to the membrane cartridge using at least one membrane cartridge containing a membrane capable of solid-liquid separation. The recovered water can be drained to the outside (Fig. 10). At this time, since the processed product can settle on the bottom of the tank, it can be separately collected and reused.

Further, as a drainage mechanism, a settling tank capable of separating a solid and a liquid by precipitation may be used. For example, a hopper type settling tank that can be generally used for water treatment, a circular settling tank with a central drive scraper, a cross-flow type settling tank, and the like can be mentioned. By using such a settling tank, a solid processed product containing the joining material removed from the target material can be separately recovered.

Alternatively, a solid and a liquid may be separated by using a multi-stage settling tank as shown in FIG. The multi-stage settling tank has a plurality of settling tanks, and can drain water from a settling tank having a high water level to a settling tank having a low water level, sequentially from above the settling tank to a settling tank in the lower stage. The processed product is settled on the bottom of each settling tank, and can be collected and reused separately.
There is no particular limitation on the number of stages of the settling tank and the capacity of each settling tank. Further, drainage from the settling tank to the next settling tank may be performed using a pump.

-Side Nozzle Heads The apparatus of the present invention may include at least one side nozzle head having at least one nozzle for injecting water onto the side surface of the target material in the processing chamber. As the side nozzle head, the nozzle head described in the above-mentioned "Method for cleaning the target material" can be used in the same manner as described above. The side nozzle head may be fixed or movable. When the side nozzle head is movable, it is preferable to move the side nozzle head along the X-axis or the Y-axis for use.
There is no particular limitation on the position and number of side nozzle heads to be arranged.
By using such a side nozzle head as needed, it is possible to perform a three-dimensional cleaning treatment not only on the main surface of the target material but also on the side surface thereof.

-Pump The device of the present invention may include a pump capable of supplying water to the nozzle head and / or the side nozzle head described above. As the pump, for example, the pump described in the above-mentioned "Method for cleaning the target material" can be used.
The pump can be connected to the nozzle head and / or side nozzle head through a line that allows fluid connection, preferably a pressure resistant line. Such lines can be arranged arbitrarily, for example, along the rod 106 shown in FIGS. 5-8, or through the inside of the rod 106. Such a pump may be arranged inside or outside the processing chamber, but is preferably arranged outside the processing chamber. Further, the number of pumps to be used is not particularly limited, and a plurality of pumps may be used.

-Control means Any of the above configurations can be appropriately controlled by using the control means. Examples of the control means include those including a CPU, ROM, RAM, and the like. The above configuration can be arbitrarily selected and electrically connected, and if necessary, the above configuration can be controlled by such control means using an electronic program.

-Drying mechanism The apparatus of the present invention may include a drying mechanism for quickly removing water adhering to the used target material after cleaning in and out of the treatment room. By removing the water, it is possible to prevent problems such as foreign matter contamination caused by the water adhering to the raw material when melting and casting the used target material after cleaning as a raw material.
The drying mechanism includes, for example, a drying mechanism by blowing dry air or a gas such as nitrogen gas onto the used target material after cleaning to blow off water adhering to the target material, or by heating with warm air or a hot plate. A drying mechanism can be adopted. When the processing chamber 104 has an opening (carry-out port) for passing the transport means 105 and the target material 101, it is preferable to provide a drying mechanism by blowing air at any adjacent portion inside or outside the opening.

[Preferable Embodiment of Cleaning Device]
The device, in a preferred embodiment,
Nozzle head and
Actuator and
Processing room and
Includes at least one component selected from the group consisting of clamps, side nozzle heads, reversing mechanisms, drainage mechanisms, drying mechanisms and transport mechanisms.

The apparatus of the present invention should not be construed as being limited to those including the above configurations.

Method for Producing Recycled Ingots Recycled ingots can be produced by melting and casting the target material treated according to the cleaning method and / or cleaning apparatus of the present invention, for example, as shown in FIG.

As a method for producing the recycled ingot, a known method may be used, and the recycled ingot can be produced through the steps of melting and casting. The melting method may be melted in the air or vacuum in an electric furnace or a combustion furnace, and the casting method includes a continuous casting method, a semi-continuous casting method, a mold casting method, a precision casting method, and a hot top. A casting method, a gravity casting method, or the like can be adopted. Further, a degassing treatment and an inclusion removal treatment may be performed between the melting and casting steps.

The production conditions of the recycled ingot, particularly the temperature, may be appropriately determined according to the metal (element) mainly contained in the target material.

For example, when the metal contained in the target material as a main component is aluminum, the cleaned target material is carbonized under vacuum (for example, 0.03 Torr) or in the atmosphere at 670 to 1200 ° C., preferably 750 to 850 ° C. A recycled ingot can be produced by dissolving in a crucible such as aluminum or alumina, stirring in the atmosphere as necessary to remove dross, and then cooling in the atmosphere.

When the metal contained in the target material as the main component is copper, the target material after cleaning is subjected to carbon or the like under vacuum (for example, 0.03 Torr) or in the atmosphere at 1100-1500 ° C, preferably 1150-1200 ° C. A recycled ingot can be produced by dissolving in a crucible such as alumina, stirring in the air as necessary to remove dross, and then cooling in the atmosphere.

In the production of the recycled ingot, it may be produced only with the target material after cleaning, or a mixture of the conventional raw material metal and the target material after cleaning may be used together. When the raw material metal and the target material after cleaning are mixed, the mixing ratio of the target material after cleaning is usually 20% by weight or more, and 50% by weight or more in order to suppress the ratio of the raw material cost in the manufacturing cost. Is preferable.

Recycled Ingots Recycled ingots that can be produced according to the method of the present invention are characterized in that they are substantially free of elements contained in impurities derived from the joining material and the supporting member, as described above, and are originally (unused). ) It can have substantially the same composition as the target material. Therefore, from such recycled ingots, a target material having substantially the same composition as the original target material can be produced again. Here, "having substantially the same composition as the original target material" means that the main metal (element) is the same and may contain the same amount of impurities as the impurities originally contained in the original target material. Means that. For example, the total amount of impurities that can be derived from the bonding material and the support member is less than 10 ppm by weight, preferably 0.1 ppm to 8 ppm, more preferably 5 ppm or less (or less), and even more preferably 0.1 ppm to 5 ppm. Yes, more preferably 0.1 ppm to 2 ppm, and the total amount of total impurities is less than 50 ppm, preferably 0.1 ppm to 20 ppm, more preferably 0.1 ppm to 10 ppm, still more preferably 5 ppm or less (or less), and further. More preferably, it may be in the range of 0.1 ppm to 5 ppm. The impurities originally contained in the original target material and the amount thereof may depend on the type of metal contained in the target material as a main component and the method for producing the original target material. In addition, the recycled ingot may be used for applications other than the target material, and may be used as a raw material for products requiring high purity such as aluminum electrolytic capacitors, hard disk substrates, corrosion resistant materials, and high-purity alumina. can.

For example, when the metal contained as the main component in the target material is aluminum, the total amount of impurities derived from the joining material and the support member contained in the recycled ingot is, for example, less than 10 ppm on a weight basis, preferably 0. .1 ppm to 8 ppm, more preferably 5 ppm or less (or less), still more preferably 0.1 ppm to 5 ppm, even more preferably 0.1 ppm to 2 ppm. Although it depends on the application, for example, an aluminum target material for a flat display is usually 50 ppm or less, preferably 0.1 ppm to 20 ppm, more preferably 0.1 ppm to 10 ppm, and even more preferably 5 ppm or less (or less). It is known that impurities of the above can be contained, and if the amount of impurities is about this level, there is no particular problem in sputtering.

When the metal contained in the target material as the main component is copper, the total amount of impurities derived from the joining material and the support member contained in the recycled ingot is, for example, less than 10 ppm on a weight basis, preferably 0. It is 05 ppm to 9 ppm, more preferably 0.05 ppm to 8 ppm. Although it depends on the application, it is known that, for example, an oxygen-free copper target material for a flat display can contain impurities of usually 100 ppm or less, preferably 0.1 ppm to 75 ppm, and more preferably 0.1 ppm to 50 ppm. If the amount of impurities is about this level, there is no particular problem in sputtering.

Moreover, since the amount of impurities contained in the recycled ingot is extremely small, the amount of such impurities can be measured by using Glow Discharge Mass Spectrometry (GDMS). Although the lower limit of GDMS quantification differs depending on the main element of the target material and the element to be detected, for example, when the metal contained as the main component of the target material is aluminum, it is usually 0.001 ppm to 0.1 ppm. For example, indium is 0.01 ppm.

As described above, according to the present invention, the used target material can be easily washed, and the cleaned target material does not substantially contain elements contained in impurities derived from the bonding material and the support member. Therefore, by reusing (or recycling) the used target material treated by such a cleaning method, it is possible to obtain a recycled ingot that is substantially free of elements contained in impurities derived from the bonding material and the support member. Therefore, the target material having substantially the same composition as the original target material can be easily recycled.

Further, in the present invention, by using the used target as the target material mainly composed of metal, it is possible to efficiently remove the joining material such as the solder material and the brazing material existing on the surface layer of the target material. It is necessary to increase the water pressure of the water jet (for example, increase it to 90 MPa or more) according to the bonding condition of the joining material on the surface layer of the target material. The joint material can be removed without damaging the target material itself.

Hereinafter, the present invention will be described in detail with reference to examples of the present invention, but the present invention is not limited to the following examples.

Example 1
Aluminum flat target material (purity: 99.999%, Vickers hardness: 15-17, dimensions: 2000 mm x 200 mm x 15 mm) and oxygen-free copper backing plate (purity: 99.99%, dimensions: 2300 mm x A sputtering target made by joining 250 mm × 15 mm) with an In solder material (thickness of the solder layer: 350 μm) (using a Sn—Zn-In solder material for metallizing the target material) is attached to the sputtering. The target material was separated from the backing plate by heating (280 ° C.) the bonding layer. The solder material adhering to the joint surface of the target material was scraped off with a silicone spatula, and the solder material was recovered as much as possible. After separating from the backing plate, the target material was cut to a size of about 300 mm × 200 mm × 15 mm.

Nozzle diameter: 0.25 mm (manufactured by Sugino Machine Co., Ltd., model number: DN-0825), 0.30 mm (manufactured by Sugino Machine Co., Ltd., model number: DN-0830), 3 nozzles each (6 in total) Using a perfect circular nozzle head (manufactured by Sugino Machine Co., Ltd., model number: MNH-2506CH) equipped with 0.30 mm nozzles at 3 locations on the outside of the nozzle head and 0.25 mm nozzles at 3 locations on the inside. , Water was sprayed onto the joint surface and the sputtering surface of the target material to clean the entire surface (water pressure: 245 MPa, water volume: 11.6 L / min, distance between the target material and nozzle head: 55 mm, scanning: 2 times, Overlap: 5 mm, nozzle head rotation speed: 1500 min ^-1 , nozzle head movement speed: 3000 mm / min). At this time, the nozzle head and the used target material were arranged so that the central axis of the nozzle head and the joint surface of the used target material were vertical, and the nozzle head was scanned in the long side direction of the used target material (nozzle). Since the surface of the head on the side where water is sprayed has a downwardly convex mountain structure, the nozzle faces diagonally with respect to the joint surface, and the water hits the joint surface diagonally). The bonding material and the metallized layer were removed from the surface of the target material after cleaning, resulting in a satin finish. The specular reflectance of the satin-shaped joint surface over a wavelength range of 300 nm to 1500 nm was measured with an ultraviolet-visible near-infrared spectrophotometer (U-4100 type, manufactured by Hitachi High-Technologies Corporation). A sample is irradiated with incident light at an incident angle of 5 ° using a 5 ° forward reflection accessory, and the reflectance of the reflected light reflected at the reflection angle of 5 ° with respect to the incident light is determined in increments of 100 nm of the incident light wavelength. rice field. The maximum was 0.4% when the wavelength of the incident light was 1300 nm, 0.3% when the wavelength was 500 nm, and 0.2% when the wavelength was 1000 nm. The specular reflectance in the entire wavelength range of 300 nm to 1500 nm of the joint surface to which the bonding material before treatment is attached is about 2 to 3% at the maximum when the wavelength of the incident light is 1300 nm, and 1 to 3% when the wavelength is 500 nm. When it was 2% and 1000 nm, it was 1 to 2%. In addition, the arithmetic mean roughness Ra was measured using a contact type surface roughness meter (Mitutoyo Co., Ltd., Surftest SJ-301) by the method specified in JIS B 0601 (2001), and the joint surface was made into a satin finish. When 3 points were measured, the average value of Ra was 19 μm. The arithmetic mean roughness Ra of the joint surface to which the joint material before the treatment was attached was 1.7 μm on average.

Using an EDXRF analyzer (EDX-700L, detection limit: about 0.01% by weight in In) manufactured by Shimadzu Corporation, the joint surface of the used target material after cleaning was analyzed (semi-quantitative analysis) under the following conditions. .. As a result, Sn, Zn, In derived from the solder material and Cu derived from the backing plate could not be detected at all on the joint surface of the used target material after cleaning. At that time, it was also confirmed whether or not X-ray peaks were detected for the elements of the components of the bonding material and the backing plate.
When the joint surface of the used target material before cleaning was analyzed by EDXRF in the same manner as above, Sn, Zn, and In derived from the solder material were 10% by weight or less, 10% by weight or less, and 1% by weight to 70, respectively. Cu present in% by weight and derived from the backing plate is present in an amount of 1% to 50% by weight, and the used target material after cleaning is derived from the solder material and the backing plate by the cleaning method of the present invention. It was found that the elements contained in the impurities were substantially not contained.
<Analysis conditions>
X-ray irradiation diameter: 10 mmφ
Excitation voltage: 10 kV (Na to Sc), 50 kV (Ti to U)
Current: 100 μA
Measurement time: 200 seconds (measured for 100 seconds at each excitation voltage)
Atmosphere: He
Tube: Rh target Filter: None Measuring method: Fundamental parameter method Detector: Si (Li) semiconductor detector

Further, the used target material after cleaning is melted under vacuum (for example, 0.03 Torr) at 850 ° C., stirred in the air to remove dross, and then cooled in the air to recycle ingots. Manufactured.
The amount of impurities contained in the recycled ingot was subjected to a trace analysis of Sn, Zn, In, and Cu using GDMS (VG9000, manufactured by VG Elemental). Table 1 below shows the analysis results of the ingot produced from the used target material (before cleaning) and the unused target material (before joining) by the same method.

From the results shown in Table 1, the amount of impurities (In, Sn, Zn derived from the solder material, Cu derived from the backing plate) contained in the recycled ingot produced using the used target material after cleaning is determined. It was found that all of them were reduced to the same level as the unused target material (before joining).

Example 2
Plate type target material made of oxygen-free copper (purity: 99.99%, Vickers hardness: 90, dimensions: 2000 mm x 200 mm x 15 mm) and backing plate made of oxygen-free copper (purity: 99.99%, dimensions: 2300 mm x 250 mm) A sputtering target made by joining (× 15 mm) with an In solder material (thickness of the solder layer: 350 μm) (using a Sn—Zn-In solder material for metallizing the target material) is used for sputtering. After that, the target material was separated from the backing plate by heating the bonding layer (280 ° C.). The solder material adhering to the joint surface of the target material was scraped off with a silicone spatula, and the solder material was recovered as much as possible. After separating from the backing plate, the target material was cut to a size of about 300 mm × 200 mm × 15 mm.

A perfect circular nozzle head (manufactured by Sugino Machine Co., Ltd., model number: MNH-2506CH) equipped with six nozzles of nozzle diameter: 0.30 mm (manufactured by Sugino Machine Co., Ltd., model number: DN-0830) is used. Then, water was sprayed onto the joint surface of the target material to clean the entire surface (water pressure: 245 MPa, water volume: 13.7 L / min, distance between the target material and the nozzle head: 25 mm, scanning: 3 times, overlap. : 5 mm, nozzle head rotation speed: 1500 cm ^-1 , nozzle head movement speed: 100 mm / min). At this time, the nozzle head and the used target material were arranged so that the central axis of the nozzle head and the joint surface were vertical, and the nozzle head was scanned in the long side direction of the used target material (water from the nozzle head was sprayed). Since the surface on the side to be sewn has a downwardly convex mountain structure, the nozzle faces diagonally with respect to the joint surface, and water hits the joint surface diagonally). The bonding material and the metallized layer were removed from the surface of the target material after cleaning, resulting in a satin finish. When the specular reflectance in the entire wavelength range of 300 nm to 1500 nm of the satin-like joint surface was measured under the same conditions as in Example 1, the maximum was 0.5% when the wavelength of the incident light was 1300 nm, and the wavelength was 500 nm. When it was, it was 0.1%, and when it was 1000 nm, it was 0.3%. The specular reflectance over the entire wavelength range of 300 nm to 1500 nm on the joint surface to which the bonded body before treatment is attached is maximum when the wavelength of the incident light is 1300 nm, is about 2 to 3%, and is 1 to 2 when the wavelength is 500 nm. %, When the wavelength was 1000 nm, it was 1 to 2%. Moreover, when the arithmetic mean roughness Ra was measured in the same manner as in Example 1, the average value of Ra was 17 μm. The arithmetic mean roughness Ra of the joint surface to which the joint before the treatment was attached was 2.1 μm on average.

Using an EDXRF analyzer (EDX-700L) manufactured by Shimadzu Corporation, the joint surface of the used target material after cleaning was analyzed under the same conditions as in Example 1. As a result, Sn, Zn, and In derived from the solder material could not be detected at all on the joint surface of the used target material after cleaning.

When the joint surface of the used target material before cleaning was analyzed by EDXRF in the same manner as above, Sn, Zn, and In derived from the solder material were 1% by weight to 20% by weight, 1% by weight to 20% by weight, respectively. It was found that the used target material after cleaning was substantially free of impurities derived from the solder material by the cleaning method of the present invention, which was present in an amount of 2% by weight to 60% by weight.

Further, the used target material after cleaning is melted under vacuum (for example, 0.03 Torr) at 1200 ° C., stirred in the air to remove dross, and then cooled in the air to recycle ingots. Manufactured.
The amount of impurities contained in the recycled ingot was subjected to a trace analysis of Sn, Zn, and In using GDMS (VG9000, manufactured by VG Elemental). Table 2 below shows the analysis results of the ingot produced from the unused target material (before joining) by the same method.

From the results shown in Table 2, the amount of impurities (In, Sn, Zn derived from the solder material) contained in the recycled ingot produced using the used target material after cleaning is the amount of the unused target material (bonding). Although a slight increase was observed as compared with the previous case), the total amount of increase was about 1.4 ppm (weight basis), and it was found that the amount of impurities was significantly reduced.

From the results of Example 2, even in the used target material containing copper as a main component, when the cleaning method according to the present invention is carried out, the used target material after cleaning having substantially the same composition as the original target material is obtained. I was able to get it. It was also found that by melting and casting the used target material after cleaning as a raw material, a recycled ingot with a significantly reduced amount of impurities can be obtained.

Example 3
Aluminum flat target material (purity: 99.999%, Vickers hardness: 15-17, dimensions: 2000 mm x 200 mm x 15 mm) and oxygen-free copper backing plate (purity: 99.99%, dimensions: 2300 mm x A sputtering target formed by bonding 250 mm × 15 mm) with the following solder material (thickness of the solder layer: 350 μm) is used by subjecting it to sputtering, and then the bonded layer is heated (280 ° C.) to obtain the target material. Was separated from the backing plate. The solder material adhering to the joint surface of the target material was scraped off with a silicone spatula, and the solder material was recovered as much as possible. After separating from the backing plate, the target material was cut to a size of about 300 mm × 200 mm × 15 mm.
The joint surface of the target material was washed under the following conditions 1 to 10. Under all conditions, the bonding material and the metallized layer were removed from the surface of the target material after cleaning, resulting in a satin finish. For the target material after cleaning, a used target material after cleaning was used under the same conditions as in Example 1 using an EDXRF analyzer (EDX-700L, detection limit: about 0.01% by weight in In) manufactured by Shimadzu Corporation. The joint surface of was analyzed. As a result, neither In, Sn, Zn derived from the solder material nor Cu derived from the backing plate could be detected on the joint surface of the used target material after cleaning. In particular, for the used target material after cleaning obtained under the following conditions 1 to 8, the target material is dissolved under vacuum (for example, 0.03 Torr) at 850 ° C. and stirred in the air to remove dross. After that, a recycled ingot was produced by cooling in the air.
The amount of impurities contained in the unused target material (before joining), the recycled ingot, and the ingot produced by the same method from the used target material (before cleaning) is determined by GDMS (manufactured by VG Elemental Co., Ltd., VG9000), respectively. ) Was used for measurement. The results are shown in Tables 3 and 4 below.

Condition 1
Solder material for joining: In
Solder material for metallizing: Sn-Zn-In
Water pressure: 200 MPa
Amount of water: 8.5 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506CH is used)
Nozzle diameter: 0.25 mm (manufactured by Sugino Machine Limited, model number: DN-0825)
Nozzle distance: 25 mm
Rotation speed: 1500min ^-1
Movement speed: 1000 mm / min
Line processing: 1 time Overlap: 5 mm
Cleaning process: Joint surface

Condition 2
Solder material for joining: In
Solder material for metallizing: Sn-Zn-In
Water pressure: 200 MPa
Amount of water: 8.5 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506CH is used)
Nozzle diameter: 0.25 mm (manufactured by Sugino Machine Limited, model number: DN-0825)
Nozzle distance: 25 mm
Rotation speed: 1500min ^-1
Movement speed: 1000 mm / min
Line processing: 1 time Overlap: 22 mm
Cleaning process: Joint surface and sputtering surface

Condition 3
Solder material for joining: In
Solder material for metallizing: Sn-Zn-In
Water pressure: 200 MPa
Amount of water: 8.5 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506CH is used)
Nozzle diameter: 0.30 mm (manufactured by Sugino Machine Limited, model number: DN-0830)
Nozzle distance: 25 mm
Rotation speed: 1500min ^-1
Movement speed: 1000 mm / min
Line processing: 1 time Overlap: 22 mm
Cleaning process: Joint surface and sputtering surface

Condition 4
Solder material for joining: In
Solder material for metallizing: Sn-Zn-In
Water pressure: 200 MPa
Amount of water: 8.5 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506CH is used)
Nozzle diameter: 0.25 mm (manufactured by Sugino Machine Limited, model number: DN-0825)
Nozzle distance: 25 mm
Rotation speed: 1500min ^-1
Moving speed: 2000mm / min
Line processing: 2 times Overlap: 22 mm
Cleaning process: Joint surface and sputtering surface

Condition 5
Solder material for joining: In
Solder material for metallizing: Sn-Zn-In
Water pressure: 200 MPa
Amount of water: 8.5 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506CH is used)
Nozzle diameter: 0.25 mm (manufactured by Sugino Machine Limited, model number: DN-0825)
Nozzle distance: 25 mm
Rotation speed: 1500min ^-1
Moving speed: 2000mm / min
Line processing: 2 times Overlap: 5 mm
Cleaning process: Joint surface and sputtering surface

Condition 6
Solder material for joining: Sn-Zn
Solder material for metallizing: Sn-Zn-In
Water pressure: 200 MPa
Amount of water: 8.5 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506CH is used)
Nozzle diameter: 0.25 mm (manufactured by Sugino Machine Limited, model number: DN-0825)
Nozzle distance: 25 mm
Rotation speed: 1500min ^-1
Movement speed: 1000 mm / min
Line processing: 2 times Overlap: 5 mm
Cleaning process: Joint surface and sputtering surface

Condition 7
Solder material for joining: In
Solder material for metallizing: Sn-Zn-In
Water pressure: 245 MPa
Amount of water: 11.6 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506CH is used)
Nozzle diameter: 0.25 mm, 0.30 mm (3 nozzles each, manufactured by Sugino Machine Limited, model number: DN-0825, DN-0830, 0.30 mm nozzle on the outside of the nozzle head, 3 on the inside 0.25mm nozzle is placed in
Nozzle distance: 55mm
Rotation speed: 1500min ^-1
Movement speed: 4000 mm / min
Line processing: 2 times Overlap: 5 mm
Cleaning process: Joint surface and sputtering surface

Condition 8
Solder material for joining: Sn-Zn
Solder material for metallizing: Sn-Zn-In
Water pressure: 245 MPa
Amount of water: 11.6 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506CH is used)
Nozzle diameter: 0.25 mm, 0.30 mm (3 nozzles each, manufactured by Sugino Machine Limited, model number: DN-0825, DN-0830, 0.30 mm nozzle on the outside of the nozzle head, 3 on the inside 0.25mm nozzle is placed in
Nozzle distance: 55mm
Rotation speed: 1500min ^-1
Movement speed: 3000 mm / min
Line processing: 2 times Overlap: 5 mm
Cleaning process: Joint surface and sputtering surface

Condition 9
Solder material for joining: In
Solder material for metallizing: Sn-Zn-In
Water pressure: 150 MPa
Amount of water: 7.3 L / min
Number of nozzles: 3 (Nozzle head is manufactured by Sugino Machine Co., Ltd., placed at a position with a pitch circle diameter (PCD) of 20 mm, and water is sprayed in the vertical direction)
Nozzle diameter: 0.35 mm (manufactured by Sugino Machine Limited, model number: DN-0835)
Nozzle distance: 25 mm
Rotation speed: 1000min ^-1
Movement speed: 1000 mm / min
Line processing: 1 time Overlap: 5 mm
Cleaning process: Joint surface

Condition 10
Solder material for joining: In
Solder material for metallizing: Sn-Zn-In
Water pressure: 245 MPa
Amount of water: 3.4 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506CH is used)
Nozzle diameter: 0.15 mm (manufactured by Sugino Machine Limited, model number: DN-0815)
Nozzle distance: 25 mm
Rotation speed: 1500min ^-1
Movement speed: 1000 mm / min
Line processing: 1 time Overlap: 5 mm
Cleaning process: Joint surface

From the results of Examples 1 and 3, when the cleaning method according to the present invention is carried out on a used target material containing aluminum as a main component, a recycled ingot having substantially the same composition as the original target material can be obtained. I understood it.

Comparative Example 1
The same used flat plate type target material as in Example 1 is cut to a size of about 100 mm × 200 mm × 15 mm, immersed in a 4.4 wt% nitric acid aqueous solution at room temperature for 20 hours, and the solder material is removed by chemical treatment. Was done. When the specular reflectance in the entire wavelength range of 300 nm to 1500 nm of the joint surface was measured by the same treatment as in Example 1, the maximum was when the wavelength of the incident light was 1300 nm, 13%, and 6.0% when the wavelength was 500 nm. When the wavelength was 1000 nm, it was 8.0%. Moreover, when the arithmetic mean roughness Ra was measured in the same manner as in Example 1, the average value of Ra was 1.1 μm. The specular reflectance over the entire wavelength range of 300 nm to 1500 nm on the joint surface to which the bonded body before treatment is attached is maximum when the wavelength of the incident light is 1300 nm, is about 2 to 3%, and is 1 to 2 when the wavelength is 500 nm. %, When the wavelength was 1000 nm, it was 1 to 2%, and the arithmetic mean roughness Ra of the joint surface before the treatment was 1.7 μm on average. Using an EDXRF analyzer (EDX-700L, detection limit: about 0.01% by weight in In) manufactured by Shimadzu Corporation, the joint surface of the used target material after chemical treatment is analyzed under the same conditions as in Example 1. did. As a result, 0.6 wt% of Cu derived from the backing plate was detected on the joint surface of the used target material after the chemical treatment, and it was found that impurities could not be removed.
Further, the used target material after the chemical treatment is melted under vacuum (for example, 0.03 Torr) at 850 ° C., stirred in the air to remove dross, and then cooled in the air for recycling. Manufactured ingots.
The amount of impurities contained in the unused target material (before joining), the recycled ingot of Comparative Example 1, and the ingot produced by melting the used target material (before chemical treatment) is determined by GDMS (VG Elemental Co., Ltd.). Manufactured by VG9000). The results are shown in Table 5 below.

In Comparative Example 1 in which only the treatment with acid was performed, impurities (that is, In, Sn, Zn, Cu) derived from the bonding material and the backing plate contained in the recycled ingot were contained even though the treatment was performed for 20 hours. The total amount of zinc is about 19 ppm on a weight basis, and it is not possible to obtain a recycled ingot having substantially the same composition as the original target material.

Example 4
Aluminum flat target material (purity: 99.999%, Vickers hardness: 14-17, dimensions: 2000 mm x 200 mm x 15 mm) and oxygen-free copper backing plate (purity: 99.99%, dimensions: 2300 mm x A sputtering target formed by bonding 250 mm × 15 mm) with the following solder material (thickness of the solder layer: 350 μm) is used by subjecting it to sputtering, and then the bonded layer is heated (280 ° C.) to obtain the target material. Was separated from the backing plate. The solder material adhering to the joint surface of the target material was scraped off with a silicone spatula, and the solder material was recovered as much as possible. After separating the target material from the backing plate, the target material was cut to a size of about 300 mm × 200 mm × 15 mm.
The joint surface, sputtering surface and side surface of 55 target materials were washed under the following condition 11. In each case, the bonding material and the metallized layer were removed from the surface of the target material after cleaning, resulting in a satin finish. Ten of the 55 washed sheets were randomly selected, and the specular reflectance of the satin-finished joint surface over a wavelength range of 300 nm to 1500 nm was measured under the same conditions as in Example 1. In each of the target materials, the specular reflectance was about 0.4% at the maximum, about 0.2% on average when the wavelength was 500 nm, and about 0.2% on average when the wavelength was 1000 nm. Moreover, when the arithmetic mean roughness Ra of 10 randomly selected sheets was measured by the same method as in Example 1, the average value of Ra was 20 μm. The specular reflectance over the entire wavelength range of 300 nm to 1500 nm on the joint surface to which the bonded body before treatment is attached is maximum when the wavelength of the incident light is 1300 nm, is about 2 to 3%, and is 1 to 2 when the wavelength is 500 nm. %, When the wavelength was 1000 nm, it was 1 to 2%, and the arithmetic mean roughness Ra of the joint surface before the treatment was 1.8 μm on average. Target material after cleaning Used target material 55 after cleaning under the same conditions as in Example 1 using an EDXRF analyzer (EDX-700L, detection limit: about 0.01% by weight in In) manufactured by Shimadzu Corporation. The joint surfaces of the sheets were analyzed. As a result, neither In, Sn, Zn derived from the solder material nor Cu derived from the backing plate could be detected on the joint surface of the used target material after cleaning. In addition, when the yield was calculated from the weight difference between the 55 target materials before and after cleaning, the average yield was 98%, and it was confirmed that the treatment could be performed with a high yield.
Next, 25 of the treated washed target materials (about 50 kg) were melted in vacuum at 800 ° C. to remove dross, and then the molten metal was poured into a carbon mold in the air to melt the molten metal in the air. Recycled ingots were produced by cooling. The amount of impurities contained in the recycled ingot was measured using GDMS (VG9000 (model number) manufactured by VG Elemental Co., Ltd.). The results are shown in Table 4 above.

Condition 11
Solder material for joining: In
Solder material for metallizing: Sn-Zn-In
Water pressure: 245 MPa
Amount of water: 18.6 L / min
Number of nozzles: 6 (Nozzle head is manufactured by Sugino Machine Limited, model number: MNH-2506-15C is used (nozzle is placed at the position of PCD 36 mm))
Nozzle diameter: 0.35 mm (manufactured by Sugino Machine Limited, model number: DN-0835)
Nozzle distance: 60 mm
Rotation speed: 2000min ^-1
Movement speed: 4000 mm / min
Line processing: 2 times Overlap: 5 mm
Cleaning process: Joint surface, sputtering surface and side surface

As shown in the results of Example 4 (Table 4), the cleaning treatment of the present invention is not affected by the variation in the thickness of the solder material of the used target, and is suitable for the treatment of a large amount of used target. It became clear.
Further, in the above Examples and Comparative Examples, the flat plate type target material has been described, but the same result can be obtained by performing the same treatment on the cylindrical target material to be joined to the backing tube by using the joining material. be able to.

This application claims its priority on the basis of Japanese Patent Application No. 2017-068470 filed in Japan on March 30, 2017, the contents of which are incorporated herein by reference in its entirety. ..

According to the present invention, for example, by cleaning a used target material as described above using the above-mentioned device, elements contained in a bonding material and impurities derived from a support member such as a backing plate or a backing tube can be removed. A used target material that is substantially free of the material can be obtained, and by producing the ingot again using such a used target material as a raw material, a recycled ingot having substantially the same composition as the original target material can be obtained. Can be obtained. According to the present invention, a target material having substantially the same composition as the original target material can be regenerated from such a recycled ingot, which is useful for recycling the target material.

1 Target material 2 Support member 3 Joint material (or joint layer)
4 Solder layer 5, 5'Metallized layer 10, 20, 30 Sputtering target 100 Equipment 101 Target material (or work)
102 Nozzle head 103 Actuator 103X X-axis slider 103Y Y-axis slider 103Z Z-axis slider 104 Processing chamber 105 Transport means 106 Rod

Claims (11)

The target material is formed from the support member of a sputtering target in which a target material composed of a metal mainly containing aluminum having a purity of 99.99% or more or copper having a purity of 99.99% or more and a support member are bonded by a bonding material. By separating and injecting only water at a pressure of 90 MPa or more onto the joint surface to which the joint material of the target material is attached, impurities derived from the joint material and the support member are bonded from the target material. The target material is removed from the surface, and at least a part of the joint surface of the target material on which the water is sprayed becomes satin-like, and water is sprayed onto the joint surface until the arithmetic average roughness Ra exceeds 10 μm. Cleaning method. The method for cleaning a target material according to claim 1, wherein the water is sprayed using a rotary nozzle head having a plurality of injection ports. The method for cleaning a target material according to claim 2, wherein the number of injection ports is 3 or more. The method for cleaning a target material according to claim 2 or 3, wherein the total discharge amount of water ejected from all the injection ports of the rotary nozzle head is 2.0 L / min or more. Any one of claims 2 to 4, wherein the water injection is performed while rotating the rotary nozzle head at a rotation speed of 500 min ^-1 or more and moving the rotary nozzle head in a fixed direction at a movement speed of 100 mm / min or more. The method for cleaning the target material according to the section. A method for producing a target material, which comprises treating the target material by the cleaning method according to any one of claims 1 to 5. A target material after cleaning, which is separated from a sputtering target in which a target material composed of aluminum having a purity of 99.99% or more or copper having a purity of 99.99% or more and a support member are bonded by a bonding material and cleaned. And
A target material after cleaning, characterized in that elements contained in impurities derived from the bonding material and the support member of the sputtering target are not detected by energy dispersive fluorescent X-ray analysis. A method for producing a recycled ingot, which comprises casting the metal using the target material obtained by the production method according to claim 6 as a raw material to obtain a recycled ingot containing the metal. A target material after cleaning, which is separated from a sputtering target in which a target material composed of aluminum having a purity of 99.99% or more or copper having a purity of 99.99% or more and a support member are bonded by a bonding material and cleaned. It is a recycled ingot containing as a raw material.
A recycled ingot characterized in that the total amount of impurities derived from the bonding material and the supporting member of the sputtering target is less than 10 ppm on a weight basis. A target material composed of aluminum with a purity of 99.99% or higher and used in sputtering.
The target material is manufactured separately from the support member.
A target material characterized in that In, Sn, Zn, and Cu are not detected by energy dispersive X-ray fluorescence analysis. A recycled ingot composed of aluminum with a purity of 99.99% or higher.
The recycled ingot contains a used target material used in sputtering as a raw material.
The target material is manufactured separately from the support member.
A recycled ingot characterized in that the total amount of In, Sn, Zn, and Cu is less than 10 ppm on a weight basis.

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